Interference mitigation by a scalable digital wireless modem

ABSTRACT

Described herein are technologies related to an implementation for dynamic adjustment of an out-of-band emission in a wireless modem, including spurious emissions, such as a Wi-FI modem, to minimize interference on a collocated or co-running downlink reception of another wireless modem residing on the same device by dynamically adjustment of a power consumption.

BACKGROUND

Wireless communication systems may use one or more channels to transferdata between a transmitter and receivers. These communication systemsmay operate according to a set of standards defined by the Institute ofElectrical and Electronics Engineers (IEEE) 802.11 committee forWireless Local Area Network (WLAN) communication.

During the transfer of data between the transmitter and receivers,multipath problems and other conditions such as presence of harmonicspurs may affect transmission and reception of data packets. Theharmonic spurs or other interference may be generated by co-runningmodems within the same portable device. The presence of the harmonicspurs or the interference that may mix with the receiving of the datapackets, for example, may cause problems with signal detecting,amplifier gain adjustment, and signal decoding among others.

As such, there is a need to mitigate presence of interference betweenco-running modems especially for a wireless fidelity (Wi-Fi) modem whichis usually treated as an aggressor component with respect to collocatedand co-running downlink cellular receiver such as long term evolution(LTE) modem.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example scenario that implements dynamicadjustment of an out-of-band emission in a Wi-Fi modem to mitigateresulting interference to a signal of another co-running modem withinthe same portable device.

FIG. 2 is an example block diagram showing components of a transceivercircuitry in a portable device.

FIG. 3 illustrates an exemplary process for implementing dynamicadjustment of an out-of-band emission in a Wi-Fi modem to minimizeinterference on a collocated or co-running downlink reception of anothermodem.

DETAILED DESCRIPTION

Described herein is a technology for implementing a method for dynamicadjustment of an out-of-band emission, including spurious emissions, ina wireless modem, such as a Wi-Fi modem, to minimize interference with acollocated and/or co-running downlink reception of another modem. Forexample, the co-running downlink reception of another modem includescellular reception, Blue Tooth (BT) reception, and the like, within thesame portable device.

As described in certain examples herein, the wireless modem isimplemented as a digital Wi-Fi modem with a programmable chain ofcomponents that may be dynamically adjusted to control an out-of-bandemission the Wi-Fi modem. For example, when a co-running or collocateddownlink cellular reception of an Long Term Evolution (LTE) modem isactive, then the Wi-Fi modem may adjust number of parallel hardwarestreams that are used within the programmable chain of components of theWi-Fi modem. Similarly, when the LTE modem is not active, then the Wi-Fimodem may limit the number of parallel hardware streams to process inputdata streams for transmission. The limited number of active parallelhardware streams within the programmable chain of components mayconserve power in the portable device. Furthermore, in these examples,the Wi-Fi modem may minimize generation of interference to LTE signalsof the co-running downlink cellular reception. The Wi-Fi modem and theLTE modem, in these examples, are collocated within the same device.

In an implementation, a detector (in certain implementations, usingpre-engineering configurations, the detector may not be implemented) isfurther coupled to the Wi-Fi modem (or victim modem) in order to detectand compare amount of Wi-Fi modem generated-interference with athreshold. For example, the out-of-band emission, including spuriousemissions, of the Wi-Fi modem is high enough to generate interference onthe LTE signal of the co-running downlink cellular reception. In thisexample, the threshold includes a pre-configured amount that is utilizedas a reference for controlling the out-of-band emission, includingspurious emission, of the Wi-Fi modem.

FIG. 1 is an example scenario 100 that utilizes a dynamic adjustment ofout-of-band emission in a Wi-Fi modem to mitigate resulting interferenceto a signal of another co-running modem within the same portable device.The scenario 100 shows a portable device 102 with an antenna 104, andanother portable device 106 with an antenna 106.

The portable devices 102 or 106 may include, but is not limited to, atablet computer, a netbook, a notebook computer, a laptop computer,mobile phone, a cellular phone, a smartphone, a personal digitalassistant, a multimedia playback device, a digital music player, adigital video player, a navigational device, a digital camera, and thelike.

The portable device 102, for example, may communicate with the otherportable device 106 in a network environment. The network environment,for example, includes a cellular network configured to facilitatecommunications between the portable device 102 and the other portabledevice 106. During this cellular network communications, cellulardownlink reception, for example, of the portable device 102 may beaffected or may receive interference from co-running and collocatedWi-Fi communication features. Thus, the implementations described hereinmay facilitate the interference or harmonic spurs mitigation, forexample, of interfering Wi-Fi signals to the cellular downlink receptionor any downlink reception within the portable device 102. Furthermore,the implementations described herein conserves power consumption in theportable device by dynamically adjusting Wi-Fi modem out-of-bandemission, including spurious emissions, depending upon whether theco-running modem is active or inactive.

FIG. 2 is an example schematic block diagram 200 showing components of atransceiver circuitry in a portable device 200. As shown, the exampleblock diagram 200 include a Wi-Fi modem 202, a detector 204, and basiccomponent of a polar digital transmitter such as oscillator 206, digitalphase locked loop (DPLL) 208, a phase modulator 210, digital poweramplifier (PA) 212, and a band pass filter 214. The Wi-Fi modem furtherincludes an IFFT 216, a regular interpolation chain 218, a configurableinterpolation chain 220, a frequency soft limiter 222, CORDIC 224,frequency hard limiter 226, fractional sampling rate converter (FSRC)228, and a parallel to serial converter (P2S) 230. Furthermore still,the Wi-Fi modem 202 includes a programmable chain component 232 thatindicates the components that may be digitally adjusted to controlout-of-band emission, including spurious emissions, of the Wi-Fi modemas described herein. The programmable components include theconfigurable interpolation chain 220, frequency soft limiter 222,CORDICs 224, frequency hard limiter 226, and the FSRC 228. It is also tobe understood that the block diagram 200 may include or coupled to oneor more processors and one or more memory components.

As a general overview of the implementations described herein,transmission of data packets from the Wi-Fi modem 202 may generateinterference to collocated and/or co-running downlink reception in anLTE modem, BT modem, and the like, within the portable device 102. Thegenerated interference may be detected and measured by the detector 204,and the measured interference is utilized by the Wi-Fi modem 202 toadjust its out-of-band emission. For example, the Wi-Fi modem 202 isconfigured to adjust components within the programmable chain component232 in order to dynamically adjust out-of-band emission, includingspurious emissions, during the transmission of data packet. In thisexample, the dynamic adjustment may depend upon whether the co-runningLTE modem, BT modem, etc. is active or inactive during the transmissionof data packet by the Wi-Fi modem 202. In case of active LTE modem, forexample, the Wi-Fi modem 202 may be switched to have a high powerconsumption mode. On the other hand, in case of inactive LTE modem, theWi-Fi modem 202 may be dynamically switched to have a low powerconsumption mode.

In an implementation, a serial symbol stream of quadrature modulateddata such as phase shift keying (PSK) or quadrature amplitude modulation(QAM) data is converted, for example, into M parallel streams. These Mstreams are then modulated onto M subcarriers via the use of size N(M<=N) IFFT 216. The N modulated outputs of the IFFT 216 are thenprocessed through the regular interpolation chain 218 and theconfigurable interpolation chain 220, which perform corresponding orderof interpolation to achieve, for example, desired up-sampling rates(e.g., 320 MSa/s). The N modulated outputs of the IFFT 216 may includeinput signals (i.e., serial symbol stream) that were converted fromfrequency domain to time domain input signals.

With the interpolated signal from the output of the configurableinterpolation chain 220, the frequency soft limiter 222 is configured tolimit frequency deviation of the interpolated signal. The streaming ofthe soft limited interpolated signal are then controlled by the CORDIC224 depending upon an amount of interference as detected and measured bythe detector 204.

For example, the detector 204 detects an active LTE modem that isreceiving LTE signals during transmission of data packets by the Wi-Fimodem 202. In this example, the CORDIC 224 is configured to activate itseight parallel hardware streams within the programmable chain component232. The eight parallel hardware streams may utilize the CORDICs 224-2to 224-16, respectively. It is to be understood that a CORDIC isdescribed; however, similar components/computers may be implemented.

In another example, the detector 204 detects an inactive LTE modem(i.e., OFF) during transmission of data packets by the Wi-Fi modem 202.In this example, the CORDIC 224 is configured to activate its twoparallel hardware streams within the programmable chain component 232.The two parallel hardware streams may utilize the CORDICs 224-2 to224-4, respectively. Controlling the number of hardware streams may atradeoff of hardware consumption versus out-of-band emission.

With continuing reference to FIG. 2, the frequency hard limiter 226 isconfigured to perform hard limiting or clipping of the output of theCORDICs 224. For example, the output of the CORDICs 224 may be strictlylimited to a certain amount prior to processing by the FSRC 228. In thisexample, the FSRC 228 is configured to sample the hard limited outputsignal of the CORDICs 224 to a desired sampling rate or to anotherdifferent sampling rate. That is, the hard limited output signal of theCORDICs 224 may have different sampling rates and as such, the FSRC 228may implement a new sampling rate to interconnect the hard limitedoutput signals with different sampling rates.

After sampling of the FSRC 228 to interconnect the hard limited outputsignals with different sampling rates, the P2S 230 may convert paralleldata streams from the FSRC 228 to serial data streams 234. As shown, theserial data streams 234 may be utilized to amplitude modulate a phasemodulated signal at the digital PA 214.

The phase modulated signal, which is received by the digital PA 214 fromthe phase modulator 210, may be dictated by control signals 236 from theP2S 230. That is the control signals 236 may include control words thatdictates phase changes in a carrier signal at the phase modulator 210.For example, the carrier signal, are facilitated by the oscillator 206and the DPLL 208.

With quadrature modulated signal from an output of the digital PA 212,the BPF 214 may attenuate unwanted replicas prior to transmission at theantenna 104.

Although the example block diagram 200 illustrates in a limited mannerbasic components of the transceiver of the portable device, othercomponents such as battery, one or more processors, SIM card, etc. werenot described in order to simplify the embodiments described herein.

FIG. 3 shows an example process flowchart 300 illustrating an examplemethod for dynamic adjustment of an out-of-band emission, includingspurious emissions, in a Wi-Fi modem to minimize interference on acollocated or co-running downlink reception of another modem. Forexample, the downlink reception of the other modem includes cellularreception, BT reception, and the like, within the same portable device.The order in which the method is described is not intended to beconstrued as a limitation, and any number of the described method blocksmay be combined in any order to implement the method, or alternatemethod. Additionally, individual blocks may be deleted from the methodwithout departing from the spirit and scope of the subject matterdescribed herein. Furthermore, the method may be implemented in anysuitable hardware, software, firmware, or a combination thereof, withoutdeparting from the scope of the invention.

At block 302, transmitting Wi-Fi data packets by a Wi-Fi modem during adownlink reception of another modem is performed. For example, the Wi-Fimodem 202 is transmitting Wi-Fi data packets during downlink cellularreception operation by the LTE modem. In this example, the Wi-Fi modem204 may be operating a high out-of-band emission level that mayinterfere with LTE signals of co-running downlink cellular reception.

At block 304, detecting and comparing amount of Wi-Fi modemgenerated-interference with a threshold is performed. For example, thedetector 204 is configured to detect and measure amount of interferencethat may be generated by the Wi-Fi modem 202 to the co-running downlinkcellular reception. In this example, the measured amount of interferenceis compared to the pre-configured threshold that is utilized as areference for controlling out-of-band emission level in the Wi-Fi modem202. Particularly, the out-of-band emission level is controlled throughan adjustment of components within the programmable chain component 232.

At block 306, adjusting out-of-band emission of the Wi-Fi modem basedupon the detected amount of Wi-Fi modem generated interference isperformed. For example, when the amount of Wi-Fi modem generatedinterference exceeds the threshold, the Wi-Fi modem 202 may lower itsout-of-band emission level to minimize interference to the co-runningdownlink cellular reception.

In another implementation, the Wi-Fi modem 202 may be co-running withthe BT modem of the same portable device, and to this end, similarimplementations as described above for the co-running 2G, LTE, 4G, andthe like, may be applied. That is, the detector 204 implements analgorithm that measures and determines the unwanted harmonic frequenciesdue to the transmitting operations of the Wi-Fi modem 202. Thedetermined unwanted harmonic frequencies are compared to the thresholdand the Wi-Fi modem 202 is adjusted accordingly to minimize theinterference.

Example is a method of interference mitigation, the method comprising:transmitting data packets by a wireless modem during a downlink cellularreception; detecting and comparing an amount of wireless modemgenerated-interference with a threshold value; and adjusting out-of-bandemission level of the wireless modem based on a detected amount ofwireless modem generated interference, wherein adjusting the out-of-bandemission level comprises adjusting a programmable chain component of thewireless modem.

In example 2, the method as recited in example 1, wherein a co-runningdownlink cellular reception includes one of a 2G, 3G, or a long termevolution (LTE) signal.

In example 3, the method as recited in example 1, wherein the thresholdis a reference for controlling the out-of-band emission level of thewireless modem.

In example 4, the method as recited in example 1, wherein adjusting theout-of-band emission level of the Wi-Fi modem further comprises:controlling number of hardware streams as a tradeoff of powerconsumption versus the out-of-band emission level.

In example 5, the method as recited in example 4, wherein controllingthe number of hardware streams is performed by a Coordinate RotationDigital Computer (CORDIC) component of the wireless modem.

In example 6, the method of example 5, wherein the CORDIC compriseseight hardware streams of about 320 MSa/s per stream.

In example 7, the method as recited in example 5, wherein the CORDICcomponent is configured to activate about eight or more parallelhardware streams during a co-running downlink cellular reception.

In example 8, the method as recited in example 5, wherein the CORDICcomponent is configured to activate at less than 7 parallel hardwarestreams when the downlink cellular reception is not active.

In example 9, the method as recited in example 1, wherein thetransmitted data packets comprise quadrature modulated data packets.

In example 10, the method as recited in any of example 1 to 9, whereinadjusting the programmable chain component comprises adjusting an orderof interpolation to obtain a desired sampling rate for modulated outputsof inverse fast fourier transform (IFFT).

In example 11, the method as recited in any of examples 1 to 9, whereinthe transmitting Wi-Fi data packets further comprises: performinginverse fast fourier transform (IFFT) of an input signal to generate amodulated output; interpolating modulated output of the IFFT; limitingthe interpolated signal; streaming the interpolated signal; clipping thestreamed interpolated signal by a frequency hard limiter; sampling theclipped streamed interpolated signal; and converting the sampledinterpolated signal into a serial signal, wherein the serial signalamplitude modulates a phase modulated signal in a digital poweramplifier (PA) prior to transmission of the data packets.

Example 12 is a device comprising: a digital wireless modem configuredto transmit Wi-Fi data packets, wherein the Wi-Fi modem furthercomprises a programmable chain component to control out-of-band emissionlevel of the transmitted data packets; and a detector component coupledto the wireless modem, wherein the detector is configured to detect andmeasure wireless modem generated interference, wherein the measurementis utilized by the wireless modem to adjust the programmable chaincomponent.

In example 13, the device as recited in example 12, wherein theprogrammable chain component comprises: a configurable interpolatorconfigured to interpolate time domain input signal; a frequency softlimiter configured to limit frequency deviation of the interpolatedsignal; a component configured to control streaming of the soft limitedinterpolated signal; a frequency hard limiter configured to perform hardlimiting or clipping of the streamed interpolated signal; and afractional sampling rate converter configured to sample the hard limitedinterpolated signal to another sampling rate.

In example 14, the device as recited in example 13, wherein thecomponent is configured to activate about eight or more parallelhardware streams during when a co-running downlink cellular reception isactive.

In example 15, the device as recited in example 13, wherein thecomponent is configured to activate less than seven two parallelhardware streams during when the downlink cellular reception isinactive.

In example 16, the device as recited in example 12, wherein the wirelessmodem generated interference comprises an interference to a co-runningdownlink cellular reception or Bluetooth (BT) reception.

In example 17, the device as recited in any of examples 12 to 16,wherein the co-running downlink cellular reception receives a 2G, 3G, ora long term evolution (LTE) signal.

Example 18 is a wireless modem comprising: an inverse fast fouriertransform (IFFT) component configured to transform a frequency domaininput signal into a time domain input signal; a configurableinterpolator configured to interpolate time domain-input signal; afrequency soft limiter configured to limit frequency deviation of theinterpolated input signal; a component configured to control streamingof the soft limited interpolated input signal; a frequency hard limiterconfigured to perform hard limiting or clipping of the streamedinterpolated input signal; and a fractional sampling rate converter(FSRC) configured to sample the hard limited interpolated input signalto another sampling rate, wherein the configurable interpolator,frequency soft limiter, component, frequency hard limiter, and the FSRCform a programmable chain component adjusted to control out-of-bandemission levels of the Wi-Fi modem in response to a measured Wi-Fi modemgenerated interference.

In example 19, the wireless modem as recited in example 18, wherein themeasured wireless modem generated interference comprises an interferenceto a co-running downlink cellular reception of a cellular modem.

In example 20, the wireless modem as recited in claim 18, wherein thecomponent is configured to control the streaming through activation ofat least two parallel hardware streams when a collocated modem is notactive.

In example 21, the wireless modem as recited in any of examples 18 to20, wherein the collocated modem receives a 2G, 3G, or an LTE signal.

What is claimed is:
 1. A method of interference mitigation, the methodcomprising: transmitting data packets by a wireless fidelity (Wi-Fi)modem; detecting presence of an active or an inactive cellular modemoperation; adjusting an emission level of the Wi-Fi modem to operate ata high power or a lower power consumption mode during the detectedactive or inactive cellular modem operation, respectively, the adjustingof the emission level of the Wi-Fi modem further comprises: performinginverse fast fourier transform (IFFT) of an input signal to generate atime domain—input signal; interpolating the time domain—input signal;limiting a frequency deviation of the interpolated input signal;controlling a streaming of the limited interpolated input signal basedon the detected active or inactive cellular modem operation, wherein aplurality of parallel connected—coordinate rotation digital computer(CORDIC) components operate at a high power consumption mode during thedetected active cellular modem operation by turning ON each of theplurality of parallel connected—CORDIC components; clipping the streamedinterpolated signal from the parallel connected—CORDIC components;sampling the clipped streamed interpolated signal; and converting thesampled interpolated signal into a serial signal, wherein the serialsignal amplitude modulates a phase modulated signal in a digital poweramplifier (PA) prior to transmission of the data packets.
 2. The methodas recited in claim 1, wherein the active cellular modem operationcomprises a 2G, 3G, or a long term evolution (LTE) signal.
 3. The methodas recited in claim 1, wherein the adjusting of the emission level ofthe Wi-Fi modem includes controlling an out-of-band emission level ofthe Wi-Fi modem.
 4. The method as recited in claim 1, wherein theplurality of parallel connected CORDIC components operate at low powerconsumption mode during the detected inactive cellular modem operationby turning ON a fewer number of CORDIC components in the plurality ofparallel connected—CORDIC components.
 5. The method as recited in claim1, wherein each (CORDIC) component controls a hardware stream of theWi-Fi modem.
 6. The method of claim 1, wherein the plurality of parallelconnected—CORDIC components comprises eight hardware streams of about320 MSa/s per stream.
 7. The method as recited in claim 1, wherein theplurality of parallel connected—CORDIC components are disposed in aprogrammable chain component of the Wi-Fi modem.
 8. The method asrecited in claim 1, wherein the plurality of parallel connected—CORDICcomponents utilizes about two CORDIC components during the detectedinactive cellular modem operation.
 9. The method as recited in claim 1,wherein the transmitted data packets comprise quadrature modulated datapackets.
 10. The method as recited in claim 1 further comprising:adjusting an order of interpolation to obtain a desired sampling ratefor an output of the inverse fast fourier transform (IFFT).
 11. Themethod as recited in claim 1, wherein the Wi-Fi modem is collocated withthe operating cellular modem.
 12. A device comprising: a digitalwireless modem configured to transmit wireless fidelity (Wi-Fi) datapackets, wherein the digital wireless modem is configured to control anemission level of the transmitted data packets based on a detectedactive or inactive transmission by a collocated cellular modem; adetector component coupled to the wireless modem, wherein the detectoris configured to detect the active or inactive transmission by thecellular modem; a programmable chain component disposed within thedigital wireless modem, the programmable chain component comprises: aplurality of parallel connected—coordinate rotation digital computer(CORDIC) components configured to control streaming of soft limitedinterpolated input signal based on the detected active or inactivetransmission by the cellular modem, wherein the plurality of parallelconnected—CORDIC components operate at high power consumption modeduring the detected active transmission by turning ON each of theplurality of parallel connected—CORDIC components.
 13. The device asrecited in claim 12, wherein the programmable chain component furthercomprises: a frequency hard limiter configured to perform hard limitingor clipping of the streamed soft limited interpolated signal from theplurality of parallel connected—CORDIC components; and a fractionalsampling rate converter configured to sample the hard limitedinterpolated signal to another sampling rate.
 14. The device as recitedin claim 12, wherein the parallel connected—CORDIC components comprisesparallel hardware streams.
 15. The device as recited in claim 12,wherein the cellular modem includes 2G, 3G, or a long term evolution(LTE) signal.
 16. The device as recited in claim 12, wherein anoperation of the digital wireless modem generates an interference to aco-running cellular modem.
 17. The device as recited in claim 12,wherein the plurality of parallel connected—CORDIC components operate atlow power consumption mode during the detected inactive cellular modemoperation by turning ON a fewer number of CORDIC components in theplurality of parallel connected—CORDIC components.
 18. A devicecomprising: a transmitter modem; a detector configured to detect anactive or an inactive transmission by the transmission modem; a wirelessfidelity (Wi-Fi) modem configured to operate at a high power or a lowerpower consumption mode during the detected active or inactivetransmission, respectively, the Wi-Fi modem further comprises: aninverse fast fourier transform (IFFT) component configured to transforma frequency domain input signal into a time domain input signal; aconfigurable interpolator configured to interpolate time domain—inputsignal; a frequency soft limiter configured to limit frequency deviationof the interpolated input signal; a plurality of parallelconnected—coordinate rotation digital computer (CORDIC) componentsconfigured to control streaming of the soft limited interpolated inputsignal based on the detected active or inactive transmission by thetransmitter modem, wherein the plurality of parallel CORDIC componentsoperate at high power consumption mode during the active transmission byturning ON multiple CORDIC component in the plurality of parallel CORDICcomponents; a frequency hard limiter configured to perform hard limitingor clipping of the streamed interpolated input signal from the pluralityof parallel connected—CORDIC components; and a fractional sampling rateconverter (FSRC) configured to sample the hard limited interpolatedinput signal to another sampling rate, wherein the new sampling ratecomprises data streams utilized to amplitude modulate a phase modulatedsignal at the transmitter mode.
 19. The wireless modem as recited inclaim 18, wherein the plurality of parallel connected-CORDIC componentsoperate at low power consumption mode during the detected inactivetransmission by turning ON a fewer number of CORDIC components in theplurality of parallel CORDIC components.
 20. The wireless modem asrecited in claim 18, wherein the detector is configured to detect andmeasure interference between collocated transmitter modem and Wi-Fimodem.
 21. The wireless modem as recited in claim 20, wherein thetransmitter modem receives a 2G, 3G, or an LTE signal.